You can still buy a super basic Nokia phone that pretty much only does that, and it lasts like a month of battery - I own one, it's great to carry around in places where you might not want to risk your super expensive smartphone.

https://www.amazon.co.uk/Nokia-1-77-Inch-Feature-Phone-Singl...

I'd happily give this to my own child so they can reach me in emergencies, but there is no risk of them going on TikTok or anything else. It's "just" a phone.